The plant lectin concanavalin A from jack bean and the two lima bean lectins, a tetramer LBL4 and an octamer LBL8, are being studied. The relationship of the metal ion requirements and saccharide binding activity are being examined by a variety of physical techniques. The characteristics of Mn2 plus and Ca2 plus binding to concanavalin A are being elucidated in an effort to explain the conformational changes which induce activity in the saccharide binding site. Nuclear magnetic resonance is being used to examine both metal ion association reactions and the nature of saccharide binding. LBL4 and LBL8 binding cell surfaces of erythrocytes and lymphocytes is being examined. In addition, the structure of these lectins is being studied. The goal is to develop these two lectins which differ in their carbohydrate binding ability as probes for detecting membrane structural differences in many types of cells including various lymphocytes and transformed cell lines.